Further observations on bone overgrowth and nerve degeneration produced by defective diet / by Edward Mellanby.

  • Mellanby, Edward, Sir, 1884-1955
Date:
[1939?]
Catalogue details

Licence: In copyright

Credit: Further observations on bone overgrowth and nerve degeneration produced by defective diet / by Edward Mellanby. Source: Wellcome Collection.

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    4 [From the Proceedings of the Physiological Society, 8 July 1939.] Journal Physiology, Vol. 96. Further observations on bone overgrowth and nerve degenera¬ tion produced by defective diet. By Edward Mellanby Widespread nerve degeneration produced in young animals by diets deficient in vitamin A (and carotene) and rich in cereals has been pre¬ viously described [Mellanby, 1931, 1934,1935]. In a detailed examination of the degenerative changes in the 8th nerve of dogs, it appeared that these were due to overgrowth of bone of the labyrinthine capsule [Mellanby, 1938 a, 6]. Macroscopic changes of the bone in the skull also suggested that bone overgrowth in other regions might well account for the degenerative changes in the trigeminal and optic nerves [Mellanby, 19385]. Trigeminal nerve After removal of the petrous ridge in these animals the abnormal curvature of the central branch of the 5th nerve can often be seen by naked eye. Serial sections show that overgrowth of this ridge and to some extent of the bone supporting the Gasserian ganglion compresses both the ganglion and the nerve centrally to the ganglion. In advanced cases the ganglion becomes elongated and the central roots of the nerve near the ganglion bent. In one case enlargement of a small portion of bone partially plugged the foramen of the 5th nerve. Optic nerve Transverse serial sections of the optic nerve and surrounding bone showed partial closure of the foramen and compression of the nerve. Pituitary body The head of the posterior clinoid process grows anteriorly and slightly downwards and there is also overgrowth of the anterior clinoid process, so that the pituitary body may be thus compressed between them and its antero-posterior length decreased. Elongation and degeneration of the cells in certain parts of the pars anterior are sometimes seen. When it was realized that bone overgrowth was so widespread, a general study of the skull was made and the frontal, parietal and occipital bones were found to be affected. In fact, the overgrowth round the foramen magnum may be so great as almost to obliterate the cisterna